The present invention is related to a process of forming a field emission electrode, and more particularly to a process of forming a field emission electrode for manufacturing a field emission array.
It""s a critical step to form a field emission electrode for manufacturing a field emission array (FEA), because the field emission electrode is used to provide stable electron beam to excite the fluorescent substances for forming an image. Certainly, the color, the brightness, the contrast and the life span of a field emission display (FED) is related to the quality of the field emission electrode.
According to the prior arts, the field emission electrode is formed by an obliquity sputtering technique. The field emission electrode with the structure of plural conoids in shape thereon is formed by the semiconductor processing technique and a high temperature oxidization technique. Certainly, the field emission electrode can be formed by further forming a metal film or a diamond film thereon for improving the quality of the field emission electrode. However, according to the prior arts, it""s not easy to form a field emission electrode with large area and good thickness uniformity at room temperature.
Accordingly, it is attempted by the present applicant to solve the above-described problems encountered in the prior arts.
According to one aspect of the present invention, a process of forming a field emission electrode for manufacturing a field emission array is provided. The process includes steps of (a) providing a substrate having a metal layer thereon, (b) forming a plurality of mask units on the metal layer and partially removing the metal layer uncovered by the mask units, (c) oxidizing a surface of the remained metal layer by an anodic oxidization method for forming a metal oxide layer thereon such that an upper portion of the unoxidized remained metal layer is in the shape of plural conoids, and (d) removing the remained mask units and the metal oxide layer.
Preferably, the substrate is made of a material selected from a group consisting of plastic, quartz and glass.
Preferably, the metal layer is selected from a group consisting of aluminum layer, tungsten layer, tantalum layer, molybdenum layer, molybdenum-tungsten alloy layer and molybdenum-tantalum alloy layer.
Preferably, the metal layer is formed on the substrate by a method selected from a group consisting of electron gun evaporation, sputtering technique and heat coating technique.
Preferably, the step (b) is performed by a photolithography technique and an etching method.
Preferably, the etching method is selected from reactive ion etching method and wet etching method.
According to another aspect of the present invention, a process of forming a field emission electrode for manufacturing a field emission array is provided. The process includes steps of (a) providing a substrate having a first metal layer thereon, (b) forming a plurality of mask units on the first metal layer and partially removing the first metal layer uncovered by the mask units, (c) oxidizing a surface of the remained first metal layer by an anodic oxidization method for forming a metal oxide layer thereon such that an upper portion of the unoxidized remained first metal layer is in the shape of plural cylinders, (d) forming a second metal layer on the metal oxide layer, and (e) removing the remained mask units.
Preferably, the substrate is made of a material selected from a group consisting of plastic, quartz and glass.
Preferably, the first metal layer and the second metal layer are selected from a group consisting of aluminum layer, tungsten layer, tantalum layer, molybdenum layer, molybdenum-tungsten alloy layer and molybdenum-tantalum alloy layer.
Preferably, the first metal layer is formed on the substrate by a method selected from a group consisting of electron gun evaporation, sputtering technique and heat coating technique.
Preferably, the second metal layer is formed on the metal oxide layer by a method selected from a group consisting of electron gun evaporation, sputtering technique and heat coating technique.
Preferably, the step (b) is performed by a photolithography technique and an etching method.
Preferably, the etching method is selected from reactive ion etching method and wet etching method.